Center finder



United States Patent 3,162,953 CENTER FENDER Dan R. Miehis, Albuquerque, N. Mex. (llitii Pate t., Carlsbad, Isl. Mex.) Filed 'Gct. 26, 19nd, No. 147,931 1 Claim. (Ci. 33-491} The present invention generally relates to a center finder and more particularly to a device for finding and marking the center of round objects such as steel shafts or the like.

The primary object of the present invention is to provide a center finder and marker having a spring loaded punch by which a center punch indentation may be formed in a surface.

Another object of the present invention is to provide a center finder and marker having a conical recess in the end thereof for receiving an object with the marking punch being disposed at the apex of the recess.

A further object of this invention is to provide a center finder and marker which is simple in construction, easy to use, accurate and is quite inexpensive to manufacture.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimrxl, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a side elevational view of the center finder and marker; and

FIGURE 2 is a longitudinal sectional view of the device taken substantially upon a plane passing along section line 2-2 of FIGURE 1.

Referring now specifically to the drawings, the numeral It generally designates the center finder and marker of the present invention which includes a cylindrical body 12 having an outwardly flared lower end portion 14 and a reduced externally threaded extension 16 at the upper end thereof.

The body 12 includes a conical recess 18 extending to the bottom edge of the outwardly flared portion 14. A longitudinal bore 26 communicates with the apex of the recess 18 and the upper end of bore 20 extends into a larger diameter longitudinal bore 22 that extends to the top end of the extension 16 of the body 12. The juncture between the bores Zil and 22 defines a shoulder 24 which forms a seat for a coil spring 26 disposed in the bore 22.

Slidable in bores-20 and 22 is an elongated center punch member 28 having a pointed lower end 30 for forming an indentation in the end of a shaft or the like when inserted into the conical recess 18 and theopposite end of the punch member 28 is struck with a hammer or the like.

Threadedly mounted on the extension 16 is a cap 32 having a knurled outer surface 34 coextensive with the surface of body 12. The cap 32 has a longitudinal extension 36 thereon having bores 38 and 40 therein which slidably receive the center punch and bore 40 receives the spring 26. The center punch 28 is provided with a cylindrical enlarged portion 42 slidable in bore 40 and engaging the upper end of the coil spring 26 as illustrated clearly in FIGURE 2.

The center finder and marker 19 is especially adapted for use by mechanics, machinists, tool and die makers and in many other trades. This device has a high degree of precision, is flexible in its use and will rapidly find the center of round objects such as a shaft inserted endwise into the recess 18. The device may be any size'desired and the components thereof may be easily replaced when worn or damaged.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

A tool for finding and marking the center of a round elongate piece of work, comprising an elongate body having a lower end and having a conical recess in said end for receiving a piece of work, an axial bore in the lower end portion of the body and opening into the recess through the apex of the latter, the diameter of the recess at the apex thereof and of the bore bein the same, a counter bore of larger diameter than said first bore in and extending axially of the body and communicating with the upper end of the first bore, a cap removably secured to the top end of said body and having a knurled outer surface coextensive with the surface of the body and forming a longitudinal extension of the body, the cap being formed with a longitudinal extension of reduced outside diameter, the said longitudinal extension of the cap having an axial bore in the upper end portion thereof of the same diameter as said first bore and opening at its lower end into a counter bore which extends through the cap and is of thesarne diameter as and is aligned with the first counterbore, a center punch shaft having thereon and intermediate its ends a cylindrical enlarged portion and having a pointed lower end, said cylindrical enlarged portion being'formed and positioned for snug sliding movement in said aligned counter bores, said shaft having the portion thereof above said cylindrical enlarged portion snugly slidably positioned in and projecting beyond the upper end of the bore in said cap extension, the

shaft having the portion thereof below said cylindrical enlarged portion extending through and snugly slidably positioned in the first bore and having said pointed end projecting into the apex portion of the recess when said cylindrical enlarged portion is at its uppermost position in the first mentioned counter bore, and a compression coil spring encircling said shaft below said cylindrical enlarged portion thereof and engaged at one end against the lower end of said cylindrical enlarged portion and supported at its other end in the first mentioned counter bore upon the bottom of the latter and urging upward movement of the shaft away from the recess, the first mentioned axial bore being of substantially greater length than the second mentioned axial bore, the shaft in its engagement in said first and second mentioned bores and the intermediately positioned cylindrical enlarged portion of the shaft in its engagement in the counter bores cooperating to maintain the shaft at all times in exact alignment with the axis of i said conical recess, in the use of the tool.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES 7 American Machinist, April 29, 1943, page 130. m 

